Flexible biasing strategy for ground-split TCR sensors

Patent metadata

Field	Value
Publication number	US-9093084-B2
Application number	US-201314099035-A
Country	US
Kind code	B2
Filing date	Dec 6, 2013
Priority date	Dec 6, 2013
Publication date	Jul 28, 2015
Grant date	Jul 28, 2015

Abstract

A first biasing potential is sent to a first input end of a first temperature coefficient of resistance (TCR) sensor having a first ground end coupled to a ground potential. A second biasing potential is sent to a second input end of a second TCR sensor having a second ground end coupled to the ground potential. The first and the second biasing potentials are changed to operate in a plurality of modes.

First claim

What is claimed is:

1. A method, comprising:
sending a first biasing potential to a first input end of a first temperature coefficient of resistance (TCR) sensor having a first ground end coupled to a ground potential; and
sending a second biasing potential to a second input end of a second TCR sensor having a second ground end coupled to the ground potential;
changing the first and second biasing potentials to operate in a plurality of modes, the plurality of modes comprising a differential mode wherein the first and second biasing potentials have the same polarity and a series mode wherein the first and second biasing potentials have opposite polarity.

2. The method of claim 1 , further comprising tuning the first and second biasing potentials to improve cancellation of common mode noise from the first and second TCR sensors.

3. The method of claim 1 , wherein the first and second biasing potentials have the same biasing potential in the differential mode.

4. The method of claim 1 , wherein the plurality of modes comprise an individual channel mode such that first biasing potential comprises a non-zero biasing potential and the second biasing potential comprises the ground potential.

5. The method of claim 4 , further comprising detecting a failure of the first TCR sensor and, in response thereto, setting the second biasing potential to the non-zero biasing potential and the first biasing potential comprises the ground potential.

6. The method of claim 4 , wherein the first TCR sensor is closer to a recording medium than the second TCR sensor, and wherein the individual channel mode improves a signal to noise ratio of a temperature signal produced by the first sensor.

7. The method of claim 1 , further comprising causing the biasing circuitry to selectably change between the plurality of modes by changing the polarity of at least one of the first and second biasing potentials.

8. An apparatus, comprising:
a head transducer that interacts with a recording medium, the head transducer comprising:
a first temperature coefficient of resistance (TCR) sensor having a first input end and a first ground end coupled to a ground potential; and
a second TCR sensor having a second input end and a second ground end coupled to the ground potential; and
biasing circuitry coupled to the first and second input ends and configured to:
apply first and second biasing potentials to the first and second input ends, and
bias the first and second TCR sensors to operate in a plurality of modes, the plurality of modes comprising a differential mode wherein the first and second biasing potentials have the same polarity and a series mode wherein the first and second biasing potentials have opposite polarity.

9. The apparatus of claim 8 , wherein the first TCR is configured to sense thermal asperities and the second TCR sensor is configured to sense contact of a magnetic recording medium.

10. The apparatus of claim 8 , wherein the first TCR sensor is configured to monitor laser power for heat assistant magnetic recording (HAMR) and the second TCR sensor is configured to sense at least one of contact and thermal asperities of the recording medium.

11. The apparatus of claim 8 , wherein the plurality of modes comprise an individual channel mode such that the biasing circuitry applies a non-zero biasing potential to the first input end and the ground potential to the second input end.

12. The apparatus of claim 11 , wherein the biasing circuitry is configured to detect a failure of the first TCR sensor and, in response thereto, apply the non-zero biasing potential to the second input end and the ground potential to the first input end.

13. The apparatus of claim 11 , wherein the first TCR sensor is closer to the recording medium than the second TCR sensor, and wherein the individual channel mode improves a signal to noise ratio of a temperature signal produced by the first sensor.

14. The apparatus of claim 8 , further comprising mode selection circuitry that causes the biasing circuitry to selectably change between the plurality of modes by changing the polarity of at least one of the first and second biasing potentials.

15. A memory system, comprising:
a disk drive, comprising:
a head transducer that interacts with a recording medium, the head transducer comprising:
a first temperature coefficient of resistance (TCR) sensor having a first input end and a first ground end coupled to a ground potential; and
a second TCR sensor having a second input end and a second ground end coupled to the ground potential; and
biasing circuitry coupled to the first and second input ends and configured to bias the first and second TCR sensors to operate in a plurality of modes, the plurality of modes comprising a differential mode wherein the first and second biasing potentials have the same polarity and a series mode wherein the first and second biasing potentials have opposite polarity.

Assignees

• Seagate Technology Llc

Inventors

• Peng Peng
• Wei Zhen
• Macken Declan
• Sedbrook Darreyl
• Khan Muhammed Mujahid

Classifications

• G11B5/3133 Primary

  including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure (G11B5/3106 takes precedence) · CPC title

• G11B5/4866 Primary

  the arm comprising an optical waveguide, e.g. for thermally-assisted recording · CPC title

• G11B5/02

  Recording, reproducing, or erasing methods; Read, write or erase circuits therefor · CPC title

• G11B5/03 Primary

  Biasing · CPC title

• G11B5/3945

  Heads comprising more than one sensitive element · CPC title